R1b1c
Haplogroup R1b is an offshoot of Haplogroup R1 (M173), characterized by the M343 marker.
Present-day Europeans with M343 also have the markers P25 and M269. This defines the more precise subgroup R1b1c.
This subgroup is believed to have been widespread in Europe before the last Ice Age, and associated with the Aurignacian culture (32,000 - 21,000 BC) of the Cro-Magnon people, the first modern humans to enter Europe. The Cro-Magnons were the first documented human artists, making sophisticated cave paintings. Famous sites include Lascaux in France, Cueva de las Monedas in Spain and Valley of Foz Côa in Portugal (the biggest open air site in Europe).
The glaciation of the ice age intensified, and the continent became increasingly uninhabitable. The genetic diversity narrowed through founder effects and population bottlenecks, as the population became limited to a few coastal refugia in Southern Europe and Asia Minor. The present-day population of R1b in Western Europe are believed to be the descendents of a refugium in the Iberian peninsula, where the R1b1c haplogroup may have achieved genetic homogeneity. As conditions eased with the Allerød Oscillation in about 12,000 BC, descendents of this group migrated and eventually recolonised all of Western Europe, leading to the dominant position of R1b in variant degrees from Iberia to Scandinavia, so evident in haplogroup maps.
A second R1b1c population, reflected in a somewhat different distribution of haplotypes of the more rapidly varying Y-STR markers, appear to have survived alongside other haplogroups in Asia Minor, from where they spread out to repopulate Eastern Europe. However, they do not have the same dominance that R1b has in Western Europe. Instead the most common haplogroup in Eastern Europe is haplogroup R1a1, often thought to be associated with a subsequent migration of Indo-Europeans (or perhaps their ancestors) from the East.
(Note that in earlier literature the M269 marker, rather than M343, was used to define the R1b haplogroup. Then, for a time (from 2003 to 2005) what is now R1b1c was designated R1b3. This shows how nomenclature can evolve as new markers are discovered and then investigated).
Source: Wikipedia contributors, "Haplogroup R1b (Y-DNA)," Wikipedia, The Free Encyclopedia, http://en.wikipedia.org/w/index.php?title=Haplogroup_R1b_%28Y-DNA%29&oldid=61192992 (accessed August 1, 2006).